1. Field of the Invention
Embodiments of the present invention relate to a semiconductor integrated circuit device and an electronic device including the same. In particular, embodiments of the present invention relate to a semiconductor integrated circuit device having a fail-safe input/output circuit providing an improved fail-safe operation.
2. Description of the Related Art
In electronic systems, e.g., mobile or portable devices operated with batteries, minimized power consumption may be desired. Accordingly, such electronic systems may include a non operational state, e.g., a “standby” mode, capable of reducing power consumption. For example, at a “standby” mode, a fail-safe circuit may be used to turn off an internal logic power, i.e., a core power, in order to reduce leakage current therein. Additionally, the fail-safe circuit may turn off an input/output (IO) power in an effort to reduce the overall power consumption further.
However, when a conventional fail-safe circuit is used to control an electronic system having a plurality of subsystems connected via a common bus, faulty signals may be generated between the subsystems. More specifically, when an electronic system includes two or more subsystems, proper data exchange between the subsystems may require setting at least one subsystem at a “standby” mode, i.e., setting the subsystem to receive and/or to transmit no data. However, when input/output (IO) ports of the “standby” subsystem are not at a high impedance state, some “indeterminate” current may flow into the “standby” subsystem via the common bus due to signal transfer of other subsystems, i.e., non-standby subsystems. For example, signal transmission between two subsystems may trigger undesired current flow into an IO port of a third subsystem set as “standby” subsystem.
Such undesired current flow may increase power consumption of the “standby” subsystem despite turned off core and/or I/O powers. Further, the current flow into the “standby” subsystem may generate noise. The noise may be interpreted as a transmission signal, thereby triggering incorrect subsystem operation and causing circuitry damage, reduced system reliability, and overall increased power consumption. Accordingly, there exists a need for a subsystem, e.g., a semiconductor device, with a fail-safe IO circuit capable of minimizing false signal transmission at a “standby” mode thereof.